Photodynamic Therapy Directed to Melanoma Skin Cancer by Thermosensitive Hydrogel Containing Chlorophyll A

Melanoma, a severe form of skin cancer intricately linked to genetic and environmental factors, is predicted to reach 100,000 new cases worldwide by 2040, underscoring the need for effective and safe treatment options. In this study, we assessed the efficacy of a photosensitizer called Chlorophyll A (Chl-A) incorporated into hydrogels (HGs) made of chitosan (CS) and poloxamer 407 (P407) for Photodynamic Therapy (PDT) against the murine melanoma cell line B16-F10. The HG was evaluated through various tests, including rheological studies, SEM, and ATR-FTIR, along with cell viability assays. The CS- and P407-based HGs effectively released Chl-A and possessed the necessary properties for topical application. The photodynamic activity of the HG containing Chl-A was evaluated in vitro, demonstrating high therapeutic potential, with an IC50 of 25.99 µM-an appealing result when compared to studies in the literature reporting an IC50 of 173.8 µM for cisplatin, used as a positive control drug. The developed formulation of CS and P407-based HG, serving as a thermosensitive system for topical applications, successfully controlled the release of Chl-A. In vitro cell studies associated with PDT exhibited potential against the melanoma cell line.

AlPc/ZnPc-based oncological photodynamic therapy for a selective eradication of leukemic cells from ovarian tissue

Due to the risk of reintroducing malignant cells, autotransplantation of cryopreserved ovarian tissue is not allowed in leukemia patients. In order to restore fertility in these patients, ex vivo purging of ovarian fragments could be proposed as a strategy to eradicate malignant cells before grafting. Photodynamic therapy (PDT), as a clinical-approved modality, is a minimally invasive and selective therapeutic for eliminating malignant cells. The present work aims therefore to evaluate the phototoxicity of two photosensitizers (aluminum phthalocyanine (AlPc) and zinc phthalocyanine (ZnPc)) on leukemia cells. To this end, two lines of malignant cells (K562 and HL-60) and isolated ovarian stromal cells (control) were treated by PDT using a diode laser with various energy densities. Cell viability after the treatment, the amount of generated reactive oxygen species, dark toxicity of the photosensitizers, and single-cell morphology were studied. Our results demonstrated that using irradiation with the energy density of 10 J/cm², 1 µM AlPc could significantly reduce the viability of K562 (4.73 ± 0.14%) and HL-60 (2.74 ± 0.31%). Similarly, the viability of these cells was reduced (K562 cells: 3.84 ± 0.81%; HL-60 cells: 6.82 ± 3.21%) with 1 µM ZnPc and an energy density of 50 J/cm². On the other hand, these PDT protocols had no significant effect on stromal cells. These findings indicate that our approach can be a promising strategy for the safe restoration of fertility in leukemia patients. However, further studies are necessary to assess its efficiency in ovarian fragments containing malignant cells to determine their eradication rate and the effect of our treatment on the survival of stromal cells and preantral follicles.

Physicochemical characterization and nano-emulsification of three species of pumpkin seed oils with focus on their physical stability

We present the chemical composition, quality parameters and antioxidant capacity of pumpkin seed oils (PSO) from Cucurbita pepo, Cucurbita maxima, and Cucurbita moschata cultivated in Brazil. In addition, PSO nanoemulsions (nanopepo, nanomax and nanomosc) were developed and their physical stabilities were assessed under long-term storage at two temperatures. Among the PSO, C. pepo presented the highest contents of polyunsaturated fatty acids, total carotenoids, and chlorophylls, but the lowest oxidative stability. Conversely, C. maxima PSO showed highest oxidative stability and total tocopherol content but the lowest chlorophyll content. Nanomax and nanopepo were more stable to droplet growth at 4 °C, while nanomosc was more stable at 25 °C. Nanopepo was the most stable formulation after the heating-cooling cycles, whereas nanomax was the most stable under centrifugation regardless the temperature. Overall, all nanoemulsions presented droplet diameter lower than 200 nm and ζ-potential approaching -30 mV until the end of storage.

Humic acid attenuation of silver nanoparticle toxicity by ion complexation and the formation of a Ag3+ coating

The use of silver nanoparticles (AgNPs) result in an inevitable contact with aquatic environments. Here we study the behavior of AgNPs and the developmental toxicity in zebrafish embryos exposed to these nanoparticles (0-10 mg/L) with and without the presence of HA (20 mg/L), using zebrafish facility water (ZFW) and zebrafish growing media (ZGM). The presence of cations and HA gave rise to a decrease in Ag ion release and ζ-potential, an increase in the hydrodynamic diameter and oxidation of the AgNP surface. The results show that the presence of HA and cations in the media, as well as the silver speciation, i.e., the unusual presence of Ag³⁺, decreases the toxicity of AgNPs (LC50_AgNPs: 1.19 mg/L; LC50_{AgNPs + HA}: 3.56 mg/L), as well as silver bioavailability and toxicity in zebrafish embryos. Developmental alterations and the LC50 (1.19 mg/L) of AgNPs in ZFW were more relevant (p ≤ 0.05) than for AgNPs in ZGM (LC50 ˃ 10 mg/L). It was demonstrated that the bioaccumulation and toxicity of AgNPs depends on several factors including AgNPs concentration, nanoparticle aggregation, dissolved silver ions, speciation of silver ions, the amount of salt in the environment, the presence of humic substances and others, and different combinations of all of these factors.

Characterization of the Cicatrization Process in Diabetic Foot Ulcers Based on the Production of Reactive Oxygen Species

The present study aims at evaluating the correlation between the free radical formation and the healing action of lower limbs' ulcers in a randomized controlled trial with the use of an adhesive derived from natural latex associated with a light-emitting diode (LED) circuit. The sample consists of 15 participants with lower limb lesions divided into three groups: group 1 case (5 participants) received the proposed dressing system adhesive of the natural latex associated with the LED circuit; group 2 control (5 participants) received the dressings at home performed by nurses according to and established by the clinic of wounds (treated with calcium alginate or silver foam); and group 3 (5 participants) also received the dressing in their homes with the use of the dressing adhesive derived from the natural latex associated with the LED circuit. The collected data were analyzed qualitatively and quantitatively by electron paramagnetic resonance for determination of free radical formation. Kruskal-Wallis statistical test was used to evaluate the effect of treatment on the lower limb's ulcer cicatrization process and its correlation with free radical. The results obtained corroborated the hypothesis about the reduction of the quantity of these molecules in the end of treatment related to the healing wound.

Thick-mode resonance of a PZT/Si wafer stack investigated by X-ray diffraction in Bragg geometry

X-ray diffraction in Bragg geometry was used to investigate the effects of standing longitudinal acoustic waves on an Si(111) wafer. A PZT/Si(111) stack with a resonant frequency of 2.34 MHz was constructed. In addition to the ultrasonic vibration, a thermal effect is evident. The thermal contribution causes an angular displacement of the Bragg profile and was mapped without time resolution. The actual ultrasonic oscillation of the surface was measured using a stroboscopic system. Bulging of the Si(111) surface was mapped out and the maximum deformation near the centre of the Si wafer was determined for a given ultrasonic power. Simple modelling using finite differences was helpful in determining the acoustic and thermal contributions.